auto-zoom/auto tracking is really crappy, if you are buying specifically for those features be prepared to be let down.
best to do it the other way around, zoom in on a choke point and then use a motion detection/line crossing/audio/sensors to zoom out as activity gets closer.. if you use BI you just need something that can do presets, then you can setup other cameras with wider views and MD zones that trigger the PTZ to go to a preset looking at that area.. if you can put a fixed wide angle camera up high with a bigger overall view it works great with a PTZ, your just using it as a fancy PTZ motion sensor.
better results, easier to tune, you can prioritize locations/zones even if you do it all outside the camera.. nobody has anything built in thats worth even enabling in most environments, it'll just wander around and miss the important stuff.. none of em can see anything out of frame once they are focused on something.
with this stuff though its best to buy a high speed PTZ, no point in trying to look at the mailbox if it takes 10 seconds to move and focus; the mailman has already moved on.. mine is normally looking at my car parked near the mailbox, because its high speed and has little distance to travel, its looking at the mailbox in less than half a second of the door opening.
